Interpretive Summary: The H5N1 high pathogenicity avian influenza (HPAI) has affecting Asia, Africa and Eastern Europe, infecting poultry and/or wild birds in 63 countries. Stamping-out or depopulation has been used in poultry to control HPAI in most countries, but vaccination was added in 15 countries to assist in control. In our study from 2002 to 2010 period, over 113 billion doses of avian influenza (AI) vaccine were used in poultry at 2-3 doses per bird. The highest coverage rate was near 100% for poultry in Hong Kong and lowest was <0.01% for poultry in 7 countries. Killed AI vaccines accounted for 95.6 percent and live vaccines for 4.4 percent. Over 99 percent of the vaccine was used in China, Egypt, Indonesia and Vietnam. Vaccination began in these four countries after H5N1 HPAI became established in domestic poultry. Vaccines prevented disease and death in chickens, and maintained rural livelihoods and food security. Low pathogenicity notifiable avian influenza (LPNAI) became reportable in 2006, but fewer outbreaks have been reported than with HPAI. Only six countries used vaccine in poultry, accounted for less than 9 percnet of the total AI vaccine usage as compared to over 91 percent of vaccine used against HPAI. In countries with established HPAI and LPNAI, development and implementation of exit strategies has been difficult.

Technical Abstract:
Twenty-nine distinct epizootics of highly pathogenic avian influenza (HPAI) have occurred since 1959. The H5N1 HPAI panzootic affecting Asia, Africa and Eastern Europe has been the largest among these, affecting poultry and/or wild birds in 63 countries. Historically, control strategies have focused on stamping-out programs which achieved eradication in 24 epizootics, but vaccination was added to the control programs in four epizootics when stamping-out alone was not effective in achieving eradication. During the 2002 to 2010 period, >113 billion doses of AI vaccine were used in at risk national poultry populations of >131 billion birds at 2-3 doses per bird in 15 countries for a vaccination coverage rate of 41.9% and a global AI vaccine coverage rate of 10.6% for all poultry. The highest coverage rate was near 100% for poultry in Hong Kong and lowest was <0.01% for poultry in France, Israel, Kazakhstan, Mongolia, The Netherlands, Democratic People’s Republic of Korea and Sudan. Inactivated AI vaccines accounted for 95.6% and live recombinant virus vaccines for 4.4% of the vaccines used. Most of the vaccines has been used in the H5N1 HPAI panzootic, with >99% of the vaccine used in China, Egypt, Indonesia and Vietnam. Implementation of vaccination in these four countries occurred after H5N1 HPAI became enzootic in domestic poultry and vaccination did not result in the enzootic infections. Vaccine usage prevented clinical disease and mortality in chickens, and maintained rural livelihoods and food security during HPAI outbreaks. Low pathogenicity notifiable avian influenza (LPNAI) became reportable to the World Organisation for Animal Health (OIE) in 2006 because some H5 and H7 low pathogenicity avian influenza (LPAI) viruses have potential to mutate to HPAI viruses. Fewer outbreaks of LPNAI have been reported than HPAI and only six countries used vaccine in control programs which accounted for <9% of the total H5/H7 AI vaccine usage as compared to >91% of vaccine used against HPAI. Six countries have used vaccine in control of LPNAI with the majority being used in Mexico, Guatemala, El Salvador and Italy. In countries with enzootic HPAI and LPNAI, development and implementation of exit strategies has been difficult.